Thermal transfer recording web roll

ABSTRACT

A coreless thermal transfer recording web roll  10  is formed by rolling a thermal transfer recording web  10 a in a roll. An inner end part  11  of the thermal transfer recording web  10 a of the thermal transfer recording web roll  10  has a tab  11 a formed at a substantially middle of the inner end part  11,  and sticking parts  11 b formed on the opposite sides of the tab  11 a, respectively. Pseudoadhesive double-coated tapes  14  are attached to the sticking parts  11 b, respectively. The pseudoadhesive double-coated tapes become tack-free after the sticking parts  11 b have been separated from the innermost layer of the thermal transfer recording web  10 a of the thermal transfer recording web roll  10.

TECHNICAL FIELD

The present invention relates to a thermal transfer recording web rollto be used on a thermal transfer printer.

BACKGROUND ART

There are a variety of thermal transfer methods using thermal transfersheets made by forming color transfer layers on base sheets. The colortransfer layers of the thermal transfer sheets are heated from behindthe thermal transfer sheets with a thermal head or the like in patternsfor yellow, magenta and cyan images of characters, figures or patterns,respectively, and the patterned yellow, magenta and cyan layers aretransferred to the surface of a transfer recording medium. Thermaltransfer methods are classified roughly by the type of the colortransfer layers into those of the sublimation transfer system and thoseof the melt transfer system. The thermal transfer method of thesublimation transfer system uses thermal transfer sheets made by formingcolor transfer layers each of a binder containing a dye that sublimatesor shifts when heated on base sheets, heats the thermal transfer sheetsfrom behind to make the dyes contained in the color transfer layerstransfer from the thermal transfer sheets to a recording medium. Thesurface of the recording medium is coated with a recording layer thatcan easily be dyed.

The thermal transfer method of the melt transfer system uses thermaltransfer sheets made by forming color transfer layers that soften, meltand become transferable when heated on base sheets, heats the thermaltransfer sheets from behind to transfer the color transfer layers to thesurface of a recording medium. Both the thermal transfer methods of thesublimation transfer system and those of the melt transfer system arecapable of forming monochromatic images and multicolor images. Informing a multicolor image, the thermal transfer method uses three orfour color thermal transfer sheets for, for example, yellow, magenta andcyan images or, when necessary, yellow, magenta, cyan and black images,and thermally transfers the color images of those colors to a recordingmedium to form color images.

The thermal transfer method holds a plurality of thermal transferrecording sheets in a stack and feeds the thermal transfer recordingsheets to a printer or uses a thermal transfer recording web roll andfeeds the thermal transfer recording web to a printer.

Recently, the thermal transfer method is used for the thermal transferrecording of a large amount of prints, and thermal transfer recordingweb rolls are used. The thermal transfer recording web roll, in general,is formed by winding a thermal transfer recording web around a feed core(bobbin). The leading edge of the recording web wound around the feedcore is attached adhesively to a take-up core and is taken upon thetake-up core after the completion of thermal transfer recording or therecording web is cut in a sheet after the completion of thermal transferrecording and the printed recording sheet is delivered.

The aforesaid conventional thermal transfer recording web roll has thefollowing problems.

(1) The conventional thermal transfer recording web roll needs a feedcore formed in a high dimensional accuracy to roll the thermal transferrecording web uniformly around the feed core without creasing thethermal transfer recording web. Thus, the feed core is inevitablycostly.

A feed core of a reduced cost may be a paper tube formed mainly of paperpulp instead of a plastic material. The paper tube is brought intocontact with a driving member of a printer to rotate the thermaltransfer recording web roll on the printer. Paper powder is produced dueto the abrasion of the paper tube by the driving member in rotating thethermal transfer recording web roll, the paper powder scatters in theprinter and, consequently, pinholes are formed in prints formed bythermal transfer printing deteriorating image quality.

(2) The core is mere waste after the thermal transfer recording web heldthereon has been used up. Since the cylindrical core is bulky for itsweight, the core cannot efficiently be carried for waste disposal. Thecore is not recycled and thrown away, which is against demand for wastereduction to avoid environmental problems.

(3) It takes time and requires troublesome work to store cores, to set acore on a take-up machine for taking up a thermal transfer recording weband to wind a thermal transfer recording web around the core.

(4) An end part of a thermal transfer recording web cannot correctlyattached to a desired part of a core in attaching the end part to thecore with an adhesive tape, an adhesive double-coated tape or a paste.The thermal transfer recording web meanders while the same is beingwound round the core and, consequently, the width of a thermal transferrecording web roll formed on the core is somewhat greater than that ofthe thermal transfer recording web. Since the thermal transfer recordingweb is wound under a specified tension and a specified pressure around ahard, cylindrical core, the position of the thermal transfer recordingweb roll formed on the core cannot be adjusted relative to the core.Therefore, the core must have a length greater than the width of thethermal transfer sheet taking into consideration the attachment of theend part of the thermal transfer recording web to an incorrect part ofthe core, and the formation of a thermal transfer recording web rollhaving a width greater than the width of the thermal transfer recordingweb. Thus, the thermal transfer recording web roll formed by winding athermal transfer recording web around a core is inevitably large.

Sometimes, the thermal transfer recording web roll is deformed whenshocks act on the thermal transfer recording web roll when the thermaltransfer recording web roll is dropped or handled improperly in carryingthe thermal transfer recording web roll or loading the thermal transferrecording web roll into a printer. It is difficult to straighten thedeformed, hard thermal transfer recording web roll.

The incorrect winding of the thermal transfer recording web around thecore and the deformation of the thermal transfer recording web rollwhile the thermal transfer recording web roll is handled affectadversely to the accuracy of print position on the thermal transferrecording web.

(5) Flaws corresponding to steps including an end part of the thermaltransfer recording web attached to the core and an end detection holeformed in the thermal transfer recording web are formed in the thermaltransfer recording web roll due to pressure and tension that act on thethermal transfer recording web, and the flaws become apparent indifferent densities of prints. FIG. 10 is a view of assistance inexplaining the formation of flaws in a thermal transfer recording web10a. In FIG. 10 flaws 3 due to an end indicating hole 2 and an end partof the thermal transfer recording web attached to a core 1. Sometimes,the hardness of the thermal transfer recording web roll is reduced byadjusting winding tension and winding pressure to prevent the foregoingproblem due to the adverse effect of the end part of the thermaltransfer recording web attached to the core and the end detecting holeon prints, which, however, could not achieve a desired effect.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a thermal transferrecording web roll to be used on a thermal transfer printer, capable ofbeing produced at a low cost without requiring much time and labor andof producing prints having a high print quality by thermal transferprinting.

According to the present invention, a thermal transfer recording webroll for use on a printer, formed by winding a thermal transferrecording web having a base web, and a recording layer formed on one ofthe surfaces of the base web; wherein the thermal transfer recording webis wound in a substantially cylindrical shape, a sticking part stickingto an innermost layer of the thermal transfer recording web is formed inan inner end part of the thermal transfer recording web, and the outersurface of the inner end part of the thermal transfer recording web isheld by the inner surface of the innermost layer of the thermal transferrecording web through the sticking part.

The thermal transfer recording web roll according to the presentinvention for use on a printer, the sticking part may become tack-freeafter the outer surface of the inner end part of the thermal transferrecording web is separated from the inner surface of the innermost layerof the thermal transfer recording web.

The thermal transfer recording web roll according to the presentinvention for use on a printer, the sticking parts may have apseudoadhesive property that enables the sticking parts to be separatedfrom the innermost layer of the thermal transfer recording web by apeeling force not higher than a peeling force corresponding to a take-uptorque exerted by the printer.

The thermal transfer recording web roll according to the presentinvention for use on a printer, the sticking part may includepseudoadhesive a double-coated tape.

The thermal transfer recording web roll according to the presentinvention for use on a printer, the inner end part of the thermaltransfer recording web may be provided with a tab for winding.

The thermal transfer recording web roll according to the presentinvention for use on a printer, the inner end part of the thermaltransfer recording web may have the tab formed in a middle part thereofwith respect to the width, and a pair of sticking parts respectively onthe opposite sides of the tab.

The thermal transfer recording web roll according to the presentinvention, the tab and the sticking parts may be demarcated by slits,respectively.

The thermal transfer recording web roll according to the presentinvention, the tab may project in a winding direction of the thermaltransfer recording web relative to the sticking parts.

The thermal transfer recording web roll according to the presentinvention, the tab may have a rectangular projection projecting from amiddle part of the inner end of the thermal transfer recording web.

The thermal transfer recording web roll according to the presentinvention, the tab may have a triangular projection projecting from amiddle part of the inner end of the thermal transfer recording web.

The thermal transfer recording web roll according to the presentinvention, an adhesive layer may be formed on the other surface of thebase web, and a release tape is applied to the adhesive layer.

The thermal transfer recording web roll according to the presentinvention, a noncontact IC tag may be attached to a part of the thermaltransfer recording web near the inner end part of the thermal transferrecording web.

The thermal transfer recording web roll according to the presentinvention, adhesive strength of the sticking part between the innermostlayer of the thermal transfer recording web and the inner end part ofthe thermal transfer recording web is higher than a peeling forcecorresponding to a take-up torque exerted by the printer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a thermal transfer recording web roll ina first embodiment according to the present invention in an unusedstate;

FIG. 2 is a plan view of an inner end part of a thermal transferrecording web unwound from the thermal transfer recording web roll shownin FIG. 1;

FIG. 3 is a perspective view of an innermost layer of a thermal transferrecording web;

FIG. 4 is a view of assistance in explaining an effect of preventing thedeformation of a thermal transfer recording web roll;

FIG. 5 is a view of assistance in explaining an effect of preventing thedeformation of a thermal transfer recording web roll;

FIG. 6 is a view of assistance in explaining the effect of a stickingpart;

FIG. 7 is a view of assistance in explaining the relation between an enddetecting method of detecting an end part to be carried out by aprinter, and an inner end part attaching method;

FIG. 8 is an end view of a thermal transfer recording web roll in asecond embodiment according to the present invention;

FIG. 9 is a view of thermal transfer recording webs in modifications;and

FIG. 10 is a view showing flaws formed in an inner end part of a thermaltransfer recording web forming a conventional thermal transfer recordingweb roll.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described withreference to the accompanying drawings.

First Embodiment

FIG. 1(A) shows an unused thermal transfer recording web roll in a firstembodiment according to the present invention, and FIG. 1(B) is asectional view of a thermal transfer recording web 10a.

A thermal transfer recording web roll 10 in the first embodiment isformed by rolling the thermal transfer recording web 10a, and has aninner end part 11, an outer end part 12 and a fastening tape 13.

As shown in FIG. 1(B), the thermal transfer recording web 10a has a baseweb 30, an intermediate layer 31 formed on one of the surfaces of thebase web 30, and a recording layer 32 formed on a surface of theintermediate layer 31.

Base Web

Preferably, the base web 30 has a mechanical strength sufficient forpreventing troubles in handling because the base web 30 holds therecording layer 32 thereon and is heated in transferring an imagethereto by thermal transfer. There are not any particular restrictionson the material forming the base web 30. The base web 30 may be formedof cellulose paper, such as condenser paper, glassine paper, parchmentpaper, paper having a high degree of sizing, synthetic paper (polyolefinpaper and polystyrene paper), wood-free paper, art paper, cast coatedpaper, wallpaper, lining paper, paper impregnated with a synthetic resinof an emulsion, paper impregnated with synthetic rubber latex,cardboard, may be formed of a film of one of polyester resins,polyacrylate resins, polycarbonate resins, polyurethane resins,polyimide resins, polyether imide resins, cellulose derivatives,polyethylene resins, ethylene-vinyl acetate copolymers, polypropyleneresins, polystyrene resins, acrylic resins, polyvinyl chloride resins,polyvinylidene chloride resins, polyvinyl alcohol resins, polyvinylbutyral resins, nylons, polyether ether ketone resins, polysulfoneresins, polyether sulfone resins, tetrafluoroethyleneperfluoroalkylvinyl ether resins, polyvinyl fluoride resins,tetrafluoroethylene ethylene resins, tetrafluoroethylenehexafluoropropylene resins, polychlorotrifluoroethylene resins, andpolyvinylidene fluoride resins. The base web 30 may be a white, opaquefilm of a material prepared by mixing one of the foregoing syntheticresins and a white pigment or filler or may be a foam web.

The base web 30 may be a laminate formed by laminating webs of theforegoing materials. A typical laminate may be a synthetic paper sheetformed by laminating a cellulose paper sheet and a synthetic papersheet, or a synthetic paper sheet formed by laminating a cellulose papersheet and a plastic film. The thickness of the base web 30 is optional.Usually, the thickness of the base web 30 is in the range of about 10 toabout 300 μm. If the adhesion between the base web 30 and theintermediate layer 31 is insufficient, it is preferable to coat thesurface of the base web 30 with a primer to finish the surface of thebase web 30 by a corona discharge treatment.

Intermediate Layer

The intermediate layer 31 is formed on the base web 30 mainly forcoloring the recording surface and opacification to conceal the base web30. A material forming the intermediate layer 31 contains two or morekinds of dyes, a white pigment, necessary additives and a resin as abinder. Resins suitable for forming the intermediate layer 31 are, forexample, thermoplastic resins, such as polyurethane resins, acrylicresins, polyester resins and polycarbonate resins, and thermosettingresins, such as resins obtained through the partial crosslinking of theaforesaid resins, crosslinked polyurethane resins, epoxy resins,melamine resins and urea resins.

The white pigment may be an inorganic pigment, such as titanium oxide,zinc oxide, barium sulfate or alumina white, an extender pigment, suchas kaolin clay, silica, magnesium carbonate or calcium carbonate, or amixture of some of those pigments.

The intermediate layer 31 is formed by an intermediate layer formingmethod including the steps of preparing a coating liquid by dissolvingor dispersing the aforesaid resin, at least two kinds of dyes, a whitepigment and, when necessary, additives in a suitable organic solvent,such as ethyl acetate, methyl ethyl ketone, toluene, xylene orcyclohexanone, coating at least one of the surfaces of the base web 30with a coating layer of the coating liquid by a coating means, such as agravure coating process, a screen printing process or a reverse-rollcoating process using a gravure plate, drying the coating layer and,when necessary, subjecting the coating layer to a crosslinking process.The intermediate layer 31 thus formed has a solid basis weight in therange of about 0.5 to 10 g/m², more preferably, in the range of 1 to 6g/m². An excessively thin intermediate layer is unable to exhibit adesired effect. The effect of an intermediate layer does not enhancebeyond a certain level even if the thickness thereof is increasedexcessively, and an excessively thick intermediate layer reduces printsensitivity.

Recording Layer

The recording layer 32 formed on the intermediate layer 31 formed on thebase web 30 receives when heated a dye transferred from a thermaltransfer sheet and records an image formed thereon. Materials suitablefor forming the recording layer 32 are polyolefin resins, such aspolypropylene resins, halogenated polymers, such as polyvinyl chlorideresins and polyvinylidene chloride resins, vinyl resins, such aspolyvinyl acetate resins, ethylene-vinyl acetate copolymers, vinylchloride-acetate copolymers and polyacrylate resins, acetal resins, suchas polyvinyl formal resins, polyvinyl butyral resins and polyvinylacetal resins, saturated and unsaturated polyester resins, polycarbonateresins, cellulose resins, such as cellulose acetate resins, styreneresins, such as polystyrene resins, acryl-styrene copolymers andacrylonitril-styrene copolymers, urea resins, melamine resins, andpolyamide resins, such as benzoguanamine resins. The recording layer 32may be formed of a compatible blend of some of the foregoing resins.

When the binder contained in the intermediate layer 31 is a resin havingactive hydrogen in hydroxyl groups or carboxyl groups, addition of acuring agent that react with active hydrogen in the recording layer 32enhances the adhesion between the intermediate layer 31 and therecording layer 32. Preferable curing agents for such a purpose areisocyanate compounds, amino compounds, and organometallic compounds.Catalysts respectively suitable for use in combination with those curingagents may be used to increase the reaction rates of the curing agent.It is preferable that the least necessary amount of curing agent isadded to the material forming the recording layer 32 in order to adhereto the intermediate layer 31.

In some cases, the resin contained in the recording layer 32 fuses witha dye binder holding a dye during the thermal transfer image recording.Therefore, it is preferable that the recording layer 32 contains alubricant, such as a phosphate, a surface-active agent, a fluorinecompound, a fluorine resin, a silicon compound, a silicone oil or asilicone resin, to provide the recording layer 32 with a satisfactoryrelease characteristic. It is particularly preferable to add a modifiedsilicone oil to and to cure the recording layer 32. Although thelubricant content is dependent on the type of the lubricant, it ispreferable that the lubricant content is the least possible value thatis sufficient for the lubricant to satisfactorily exercise its effect inthe range of 1 to 20 parts by weight on the solid bases. When a modifiedsilicone oil having reactive groups capable of reacting with the curingagent is added to the recording layer 32, it is preferable that theratio of the equivalent weight of the reactive groups of the modifiedsilicone oil to that of the reactive groups of the curing agent is inthe range of 1:1 to 1:10. A releasing layer, i.e., a layer of theaforesaid lubricant or a layer of a mixture of the binder and theaforesaid lubricant, may be formed on the recording layer instead ofadding the lubricant to the recording layer.

The recording layer 32 is formed by applying a coating liquid preparedby dissolving or dispersing a mixture of a resin and necessary additivesin an organic solvent to the intermediate layer 31 by a coating process,such as a gravure printing process, a screen printing process or areverse-roll coating process using a gravure plate, in a coating layerand drying the coating layer. Although the recording layer may have anythickness, the thickness of the recording layer, in general, is in therange of 1 to 50 μm.

Slip Layer

A slip layer 33 may be formed on the back surface of the base web 30 ofthe thermal transfer recording web 10a to improve the facility ofmechanical carrying of the thermal transfer recording web 10a and toprevent the curling of the thermal transfer recording web 10a. It ispreferable to add a proper amount of an organic or inorganic filler tothe binder or to use a resin having a high lubricity, such as apolyolefin resin or a cellulose resin, as the binder. The slip layer 33may be formed of a mixture prepared by adding as additives, an organicfiller, such as an acrylic filler, a nylon filler, a Teflon® filler or apolyethylene wax, and an inorganic filler, such as silicon dioxide or ametal oxide, to a resin, such as an acrylic resin, a cellulose resin, apolycarbonate resin, a polyvinyl acetal resin, a polyvinyl alcoholresin, a polyamide resin, a polystyrene resin, a polyester resin or ahalogenated polymer. An acrylic resin is preferable and an acrylpolyolis most preferable. It is preferable to use a resin obtained by curingan acrylpolyol with a curing agent.

The slip layer 33 is formed by applying a coating liquid prepared bythoroughly kneading a mixture prepared by mixing the aforesaid resin, afiller, a solvent and a diluent to the back surface of the base web 30by a coating process, such as a gravure printing process, a screenprinting process or a reverse-roll coating process using a gravureplate, in a coating layer and drying the coating layer. Although theslip layer 33 may have any thickness, the thickness of the slip layer33, in general, is in the range of 1 to 10 μm

Adhesive Layer

An adhesive layer 34 of an adhesive resin, such as an acrylate resin, apolyurethane resin or a polyester resin, may be formed on the surfaceand/or the back surface of the base web 30. The adhesive layer 34 isformed by applying a coating liquid containing the aforesaid resin tothe surface and/or the back surface of the base web 30 by a coatingprocess, such as a gravure printing process, a screen printing processor a reverse-roll coating process using a gravure plate, in a coatinglayer and drying the coating layer. The surface and/or the back surfaceof the base web 30 may be processed by a corona discharge processinstead of coating the surface and/or the back surface of the base web30 with the coating layer to enhance adhesion between the base web 30and the layer formed on the former.

Antistatic Layer

An antistatic layer 35 may be formed on at least one of the outermostsurfaces of the thermal transfer recording web 10a. The antistatic layer35 is formed by spreading a coating liquid prepared by dissolving ordispersing a fatty ester, a sulfate, a phosphate, an amide, a quaternaryammonium salt, betaine, an amino acid or an ethylene oxide additionproduct in a solvent. The antistatic layer 35 may be formed by spreadinga conductive resin produced by introducing a group having an antistaticeffect, such as a quaternary ammonium salt, a phosphate, an ethosulfate,a vinyl pyrrolidone or sulfonic acid, into an acrylic resin, a vinylresin or a cellulose resin or an antistatic resin produced through thecopolymerization of such an antistatic group and such a resin.Preferably, the basis weight of the antistatic layer 35 is in the rangeof 0.001 to 0.1 g/m². The antistatic layer 35 may be formed by aspraying process or a transfer process instead of a coating process. Thethermal transfer recording web 10a provided with the antistatic layer 35has an excellent antistatic property and is capable of preventingdouble-sheet feeding.

The inner end part 11 of the rolled thermal transfer recording web 10ahas a tab 11a and sticking parts 11b.

FIG. 2 shows the inner end part 11 of the thermal transfer recording web10a unwound from the thermal transfer recording web roll 10.

A winding machine used in a manufacturing process catches the thermaltransfer recording web 10a by the tab 11a in winding the thermaltransfer recording web 10a in the thermal transfer recording web roll10. The inner end part 11 is cut into three parts by slits 11c. The tab11a is the middle one of those three parts.

The two parts on the opposite sides, with respect to the width, of thetab 11a are the sticking parts 11b. Pseudoadhesive double-coated tapes14 are attached to the back surfaces (outer surfaces) of the stickingparts 11b. The pseudoadhesive double-coated tapes 14 stick to theinnermost layer, i.e., the first layer, of the thermal transferrecording web roll 10 formed by rolling the thermal transfer recordingweb 10a. The sticking parts 11b provided with the pseudoadhesivedouble-coated tapes 14 loose their sticking property after the stickingparts 11b have been separated from the inner surface of the innermostlayer of the thermal transfer recording web 10a.

The outer end part 12 is fastened temporarily to the thermal transferrecording web 10a with a fastening tape 13 to prevent the thermaltransfer recording web roll 10 from coming loose.

FIG. 3 shows the innermost layer formed by rolling the thermal transferrecording web 10a.

The sticking parts 11b of the inner end part 11 of the thermal transferrecording web 10a stick. Thus, the inner end part 11 is held in place onthe innermost layer as shown in FIG. 3 without using any core.

Since the winding machine grips the tab 11a in winding the thermaltransfer recording web 10a, the tab ha is curved permanently radiallyinward as shown in FIGS. 1 and 3. If the inner end part 11 is entirely asticking part, the inner end part 11 extends radially inward andinterferes with a mounting shaft 5a included in a printer 5 in loadingthe thermal transfer recording web roll 10 into the printer 5, whichmakes a loading operation difficult and cause faulty loading.

In this embodiment, the tab 11a is at the middle, with respect to thewidth, of the inner end part 11 of the thermal transfer recording web10a, and the sticking parts 11b extend in a circular shape conforming tothe innermost layer. Therefore, the tab 11a will not obstruct theinsertion of the mounting shaft 5a of the printer 5 into the thermaltransfer recording web roll 10. Thus, the thermal transfer recording webroll 10 can easily and correctly loaded into the printer 5.

FIGS. 4 and 5 are views of assistance in explaining an effect ofpreventing the deformation of the thermal transfer recording web roll10.

A thermal transfer recording web roll provided with a core 1 is formedby winding a thermal transfer recording web around the hard cylindricalcore 1 under a specified tension and a specified pressure around a hard,cylindrical core 1, and therefore the position of the thermal transferrecording web roll formed on the core cannot be adjusted relative to thecore 1. Although the thermal transfer recording web roll 10 in the firstembodiment is easily deformable because the thermal transfer recordingweb roll 10 in the first embodiment, which is a coreless thermaltransfer recording web roll, is formed by winding the thermal transferrecording web 10a under low pressure and low tension, the shape of thethermal transfer recording web roll 10 can easily be corrected, there isno problem in the position of the thermal transfer recording web roll 10relative to a core, and hence the thermal transfer recording web roll 10is easy to use and handle.

FIG. 6 is a view of assistance in explaining the effect of the stickingparts 11b of the thermal transfer recording web 10a.

If the inner end part 11 of the thermal transfer recording web roll 10is not provided any parts corresponding to the sticking parts 11b andthe thermal transfer recording web roll 10 is used on the printer 5, thethermal transfer recording web 10 loosens and the diameter of thethermal transfer recording web roll 10 increases at a stage immediatelybefore the thermal transfer recording web 10 is used up. Consequently,the thermal transfer recording web 10a comes into contact with the innersurfaces of walls of the printer 5 in the vicinity of the thermaltransfer recording web roll 10, the thermal transfer recording web 10ais rubbed with the walls and scraps and fragments of the thermaltransfer recording web 10a adhere to the inner surfaces of the walls ofthe printer 5. Dyes cannot be printed on thus flawed or scratched partsof the thermal transfer recording web 10a and on parts of the recordinglayer 32 covered with the scraps and fragments of the thermal transferrecording web 10a scattered in the printer 5, and the printing ribboncannot normally be separated form those parts of the thermal transferrecording web 10a.

If the inner end part 11 of the thermal transfer recording web roll 10is not provided any parts corresponding to the sticking parts 11b, thethermal transfer recording web 10a needs to be wound in several turns tohold the thermal transfer recording web roll 10 in its shape. Whenflanges 5b included in the printer 5 are pressed against the oppositeends of the thermal transfer recording web roll 10 to hold the thermaltransfer recording web roll 10 in place, the thermal transfer recordingweb roll 10 cannot be held when the thermal transfer recording web 10ais wound in one layer.

Since the inner end part 11 of the thermal transfer recording web roll10 in this embodiment is provided with the sticking parts 11b, theflanges 5b of the printer 5 are able to hold the thermal transferrecording web roll 10 between the flanges 5b even if the thermaltransfer recording web roll 10 has only one layer.

Although the pseudoadhesive double-coated tapes 14 are attached to thesticking parts 11b in this embodiment, an optimum method of attachingthe sticking parts 11b to the inner surface of the innermost layer mustselectively be determined taking into consideration an end detectingmethod by which the printer detects the end of the thermal transferrecording web 10a of the thermal transfer recording web roll 10.

FIG. 7 is a view of assistance in explaining the relation between an enddetecting method of detecting an end part to be carried out by theprinter, and an attaching method of attaching the inner end part of thethermal transfer recording web 10a to the innermost layer of the thermaltransfer recording web roll 10.

When the printer 5 is provided with a sensor that detects light passedthrough an end indicating hole 2 formed in the thermal transferrecording web 10a or light reflected from an end indicating mark 2amarked on the thermal transfer recording web 10a of the thermal transferrecording web roll 10, a thermal transfer recording web feed mechanismincluded in the printer 5 stops when the sensor detects the light passedthrough the end indicating hole 2 or the light reflected from the endindicating mark 2a. Therefore, the sticking parts 11b may be of anyshape provided that the sticking parts 11b are attached to the innermostlayer (FIGS. 7(A) and 7(B)).

When the thermal transfer recording web 10a of the thermal transferrecording web roll 10 is provided with neither any hole corresponding tothe end indicating hole 2 nor any mark corresponding to the endindicating mark 2a, and the printer 5 detects a change in the torqueacting on the thermal transfer recording web feed mechanism, the shapeof the sticking parts 11b must selectively be determined so that theprinter 5 is able to detect the change in the torque (FIGS. 7(C) and7(D)).

When the approach of the end is indicated by the duration of a maximumtake-up torque for a predetermined time, the sticking parts 11b may beattached to the innermost layer with adhesive means capable of stickingto the innermost layer, such as adhesive double-coated tapes 14a,adhesive tapes or an adhesive (FIG. 7(E)). The adhesive strength bondingthe sticking parts 11b to the innermost layer must withstand the peelingeffect of a take-up torque applied to the thermal transfer recording webroll 10 by the printer 5.

When the approach of the end is indicated by the reduction of thetake-up torque to naught, the printer stops upon the separation of thesticking parts 11b from the innermost layer. Therefore, the stickingsurfaces of the sticking parts 11b must become tack-free (nonadhesive)after the sticking parts 11b have been separated from the innermostlayer. The bond strength between the sticking parts 11b and theinnermost layer should not be excessively high, and the sticking parts11b must be separated from the innermost layer when a torque not higherthan the take-up torque and not lower than a predetermined level acts onthe thermal transfer recording web roll 10. Therefore, it is preferableto use the pseudoadhesive double-coated tapes 14 (FIG. 7(F)).

The thermal transfer recording web 10a of the thermal transfer recordingweb roll 10 in this embodiment is provided with the end indicating hole2 as shown in FIG. 3 and is intended to be used on a printer 5 thatdetects the end indicating hole. However, since the sticking parts 11bare attached to the innermost layer with the pseudoadhesivedouble-coated tapes 14, the thermal transfer recording web roll 10 canbe used on a printer 5 that detects neither an end indicating hole noran end indicating mark and decides that the thermal transfer recordingweb 10a is substantially used up when the take-up torque decreases to anaught.

The pseudoadhesive double-coated tape 14 will be explained.

The pseudoadhesive double-coated tape 14 has either of the following twoforms.

(1) Release tape/Adhesive layer/Nonwoven or paper tape/Resinlayer/Plastic base/Adhesive layer/Release tape

(2) Release tape/Adhesive layer/Plastic base/Resin layer/Plasticbase/Adhesive layer/Release tape

In forming the pseudoadhesive double-coated tape of the form (1), amolten resin is extruded through a T-die or the like on a nonwoven tape(or a plastic base) to form a resin layer, and the nonwoven tape (or theplastic base) is laminated to a plastic base (or a nonwoven tape), anadhesive layer is formed on the surface of the nonwoven tape (or theplastic base), an adhesive layer is formed on the surface of the plasticbase (or the nonwoven tape), and then release tapes are applied to theadhesive layers.

Suitable resins for forming the resin layer include polypropylene resin,such as Novatec-P available from Mitsubishi Kagaku, polyolefin resins,such as TPX (polymethylpentene) available from Mitsui Kagaku, polyamideresins, ionomers and nylons.

Since the thermal transfer recording web roll 10 in the first embodimentis a coreless roll, the thermal transfer recording web can be rolledwithout using any core and much time and labor at a low cost, andpictures of satisfactory picture quality can be printed by thermaltransfer printing on the thermal transfer recording web.

Second Embodiment

FIG. 8 shows a thermal transfer recording web roll 10 in a secondembodiment according to the present invention.

The thermal transfer recording web roll 10 in the second embodiment isthe same in construction as the thermal transfer recording web roll 10in the first embodiment, except that the former is provided with a radiofrequency identification tag 20 near an inner end part 11 of the thermaltransfer recording web 10a.

The radio frequency identification tag 20 is an on contact IC tag (RFID)attached to a part near the inner end part 11 of the inner surfaces ofthe thermal transfer recording web roll 10. Information about the type,size and such of the thermal transfer recording web roll 10 is recordedon the noncontact IC tag. When the thermal transfer recording web roll10 is loaded into a printer 5, a read-write head R/W reads theinformation held by the noncontact IC tag.

Since the radio frequency identification tag 20 is attached to thethermal transfer recording web roll 10, the coreless thermal transferrecording web roll 10 is able to hold necessary information and theprinter is able to use the information.

Modifications

The present invention is not limited in its practical application to theforegoing embodiments, various modifications of the foregoingembodiments may be made and various changes are possible in theforegoing embodiments without departing from the scope of the presentinvention.

For example, although the tab 11a and the sticking parts 11b arearranged along the width of the thermal transfer recording web 10a inthe foregoing embodiments, the tab 11a may be formed in a middle partwith respect to the width of the thermal transfer recording web 10a soas to protrude in the winding direction, and a sticking part 11b may beformed in the inner end part as shown in FIGS. 9(A) and 9(B). In FIGS.9(A) and 9(B), the sticking part 11b and a pseudoadhesive double-coatedtape 14 are indicated by broken lines.

An adhesive layer 37 may be formed on a surface of the base web 30,opposite to the recording layer 31 of the thermal transfer recording web10a of the thermal transfer recording web roll 10 in the firstembodiment, and a release tape 38 may be applied to the adhesive layer37 to use the thermal transfer recording web 10a as a photograph sealingweb.

As apparent form the foregoing description, the present invention hasthe following effects.

(1) The thermal transfer recording web roll 10 can be produced at a lowcost because the thermal transfer recording web roll 10 is formed byrolling the thermal transfer recording web 10a in a substantiallycylindrical shape without using any core.

Since the thermal transfer recording web roll 10 is not provided withany core, the thermal transfer recording web roll 10 does not produceunnecessary waste.

The deformation of the thermal transfer recording web roll 10 can easilybe corrected and handling of the thermal transfer recording web roll 10is facilitated.

Any flaws corresponding to steps including an end detection hole formedin the thermal transfer recording web are not formed in the thermaltransfer recording web and pictures can be formed in satisfactorypicture quality on the thermal transfer recording web.

(2) Since the thermal transfer recording web 10a is provided with thesticking parts 11b at parts of the inner end part 11 that is in contactwith the inner surface of the innermost layer of the thermal transferrecording web 10a, the thermal transfer recording web roll 10 will notloosen immediately before the thermal transfer recording web 10a of thethermal transfer recording web roll 10 is used up and thereby troublesthat may result from the loosening of the thermal transfer recording webroll 10 can be avoided.

(3) Since the sticking surfaces of the sticking parts 11b becometack-free after the sticking parts 11b have been separated from theinnermost layer, the thermal transfer recording web roll 10 can be usedon a printer that detects the end of the thermal transfer recording web10a by any detecting method.

(4) The pseudoadhesive sticking parts become tack-free surely and simplyafter the same have been separated from the innermost layer.

(5) since the tab 11a is at the middle of the inner end part 11 of thethermal transfer recording web 10a, the tab 11a will not obstruct theloading operation for loading the thermal transfer web roll 10 into theprinter 5 and the thermal transfer recording web roll 10 can easily andcorrectly loaded into the printer 5.

(6) Since the inner end part 11 of the thermal transfer recording web10a is provided with the slits 11c demarcating the tab 11a and theadjacent sticking parts 11b, any scraps and fragments are not producedin manufacturing the thermal transfer recording web roll 10.

(7) When the tab 11a projects in the winding direction, the thermaltransfer recording web 10a can easily be attached to the windingmachine.

(8) When the adhesive layer 37 is formed on the surface, opposite thesurface on which the recording layer 32 is formed, of the base web 30,and the release tape 38 is attached to the adhesive layer 37, a corelessthermal transfer recording web roll for use on a photograph sealingprinting machine can be formed, and even an unskilled operator is ableto handle the coreless thermal transfer recording web roll easily.

(9) When the thermal transfer recording web roll 10 is provided with thenoncontact IC tag 20 in a part of the thermal transfer recording web 10anear the inner end part 11, the coreless thermal transfer recording webroll 10 is able to hold various pieces of information.

1. A thermal transfer recording web roll for use on a printer, formed by winding a thermal transfer recording web having a base web, and a recording layer formed on one of the surfaces of the base web; wherein the thermal transfer recording web is wound in a substantially cylindrical shape, a sticking part sticking to an innermost layer of the thermal transfer recording web is formed in an inner end part of the thermal transfer recording web, and the outer surface of the inner end part of the thermal transfer recording web is held by the inner surface of the innermost layer of the thermal transfer recording web through the sticking part, wherein the inner end part of the thermal transfer recording web is provided with a tab for winding.
 2. The thermal transfer recording web roll for a printer according to claim 1, wherein the sticking part becomes tack-free after the outer surface of the inner end part of the thermal transfer recording web is separated from the inner surface, of the innermost layer of the thermal transfer recording web.
 3. The thermal transfer recording web roll for a printer according to claim 1, wherein the sticking part has a pseudoadhesive property that enables the sticking part to be separated from the innermost layer of the thermal transfer recording web by a peeling force not higher than a peeling force corresponding to a take-up torque exerted by the printer.
 4. The thermal transfer recording web roll for use on a printer according to claim 3, wherein the sticking part includes a pseudoadhesive a double-coated tape.
 5. The thermal transfer recording web roll for use on a printer according to claim 1, wherein the inner end part of the thermal transfer recording web has the tab formed in a middle part thereof with respect to the width, and a pair of sticking parts respectively on the Opposite opposite sides of the tab.
 6. The thermal transfer recording web roll for use on a printer according to claim 5, wherein the tab and the sticking parts, are demarcated by slits, respectively.
 7. The thermal transfer recording web roll for use on a printer according to claim 1, wherein the tab projects in a winding direction of the thermal transfer recording web relative to the sticking part.
 8. The thermal transfer recording web roll for use on a printer according to claim 7, wherein the tab has a rectangular projection projecting from a middle part of the inner end of the thermal transfer recording web.
 9. The thermal transfer recording web roll for use on a printer according to claim 7, wherein the tab has a triangular projection projecting from a middle part of the inner end of the thermal transfer recording web.
 10. The thermal transfer recording web roll for use on a printer according to claim 1, wherein an adhesive layer is formed on the other surface of the base web, and a release tape is applied to the adhesive layer.
 11. The thermal transfer recording web roll for use on a printer according to claim 1, wherein a noncontact IC tag is attached to a part of the thermal transfer recording web near the inner end part of the thermal transfer recording web.
 12. The thermal transfer recording web roll for use on a printer according to claim 1, wherein adhesive strength of the sticking part between the innermost layer of the thermal transfer recording web and the inner end part of the thermal transfer recording web is higher than a peeling force corresponding to a take-up torque exerted by the printer.
 13. A thermal transfer recording web roll for use on a printer, formed by winding a thermal transfer recording web having a base web, and a recording layer formed on one of the surfaces of the base web; wherein the thermal transfer recording web is wound in a substantially cylindrical shape, a sticking part sticking to an innermost layer of the thermal transfer recording web is formed in an inner end part of the thermal transfer recording web, the outer surface of the inner end part of the thermal transfer recording web is held by the inner surface of the innermost layer of the thermal transfer recording web through the sticking part, and an end indicating hole or an end indicating mark is formed at an upstream part of the sticking portion of the innermost layer for indicating the inner end part of the thermal transfer recording web.
 14. The thermal transfer recording web roll for use on a printer according to claim 13, wherein the sticking part becomes tack-free after the outer surface of the inner end part of the thermal transfer recording web is separated from the inner surface of the innermost layer of the thermal transfer recording web.
 15. The thermal transfer recording web roll for use on a printer according to claim 13, wherein the sticking part has a pseudoadhesive property that enables the sticking part to be separated from the innermost layer of the thermal transfer recording web by a peeling force not higher than a peeling force corresponding to take-up torque exerted by the printer.
 16. The thermal transfer recording web roll for use on a printer according to claim 15, wherein the sticking part includes pseudoadhesive double-coated tape.
 17. The thermal transfer recording web roll for use on a printer according to claim 13, wherein the inner end part of the thermal transfer recording web is provided with a tab for winding.
 18. The thermal transfer recording web roll for use on a printer according to claim 17, wherein the inner end part of the thermal transfer recording web has the tab formed in a middle part thereof with respect to the width, and further comprising a pair of sticking parts respectively on the opposite sides of the tab.
 19. The thermal transfer recording web roll for use on a printer according to claim 18, wherein the tab and the sticking parts are demarcated by slits, respectively.
 20. The thermal transfer recording web roll for use on a printer according to claim 17, wherein the tab projects in a winding direction of the thermal transfer recording web relative to the sticking part.
 21. The thermal transfer recording web roll for use on a printer according to claim 20, wherein the tab has a rectangular projection projecting from a middle part of the inner end of the thermal transfer recording web.
 22. The thermal transfer recording web roll for use on a printer according to claim 20, wherein the tab has a triangular projection projecting from a middle part of the inner end of the thermal transfer recording web.
 23. The thermal transfer recording web roll for use on a printer according to claim 13, wherein an adhesive layer is formed on the other surface of the base web, and a release tape is applied to the adhesive layer.
 24. The thermal transfer recording web roll for use on a printer according to claim 13, wherein a noncontact IC tag is attached to a part of the thermal transfer recording web near the inner end part of the thermal transfer recording web.
 25. The thermal transfer recording web roll for use on a printer according to claim 13, wherein adhesive strength of the sticking part between the innermost layer of the thermal transfer recording web and the inner end part of the thermal transfer recording web is higher than a peeling force corresponding to a take-up torque exerted by the printer. 